Bayou that wont run but with choke 1/2 on

[JT Gray]

Hi all first post. I have a 94 bayou 300 i got new that one day took a notion to only run with the choke 1/2 open. with the miles i have put on it i just thought it had gave up the ghost. until about a month ago i was over at a friends house and he was talking about his 96 bayou that was doing the same thing. now i know for a fact his didnt have the miles mine did so we got togather and said carb. after 3 cleanings of my carb im almost for certain its not the carb. now yesterday he told me of a friend of his that has a 97 that is doing the same thing. symptoms are only runs with the choke 1/2 open if u try to ride it that way u dont have much if any power going down hill it pops out the tailpipe and the ever lovely spark knock got to love the spark knock. hope u can help and thnx. love the smilie face but im like a cat give me a paper bag and im happy for hrs lol

[86klf300guy]

well that guestions been a main subject around here you say you have cleaned the carb 3 times and still haveing an issue along with a freinds can i ask what alttitude you are at the air flow screw may have something to do with this but normally its a blocked up air jet or main fuel jet or a bad float set up and or needle so whats going on is you are getting to much air and not enough fuel thats were the choke 1/2 open is helping with but make sure you have good flow out of the petcok to the carb then reset float hieghts as a starting point, i have gone as far as putting a thin washer on the needle that sets in the diophram to set the needle a bit higher up to fattin up the fuel mix its like doin a needle clip adjustment on a mikuni what that does is let more fuel past the main jet that way you can set the air flow screw out a bit more for more power and also will have to rest idle cause it will amke it higher hope thios may help out -corey-

[RCW]

If the carburetor was fully disassembled and cleaned, including all the small bleed holes in the needle jet holder (the brass tube that screws in and holds the needle jet in the carb body), and the various passages, then look at the following:

If you live in a state with oxygenated fuel (ethanol alcohol in the gas) you likely have a cracked or broken diaphragm (Kaw calls this a vacuum valve). Disassemble the carburetor and inspect the diaphragm for any defects, then replace with one of the new ones approved for crap fuel if necessary.

It is also a good idea to check the O-ring between the spacer and the head, and the second O-ring between the spacer and the rubber carb mount; and then check the rubber carb mount for cracks and to be sure the carb is tightly mounted and clamped.

[ricms]

I had the same problem with my 91 found to be the cdi was bad

[gt2003]

Not to sound stupid, but have you checked the fuel? Is it fresh? I've got a 2004 bayou that ran great 1 year but when I went to start it the next year it wouldn't run except without the choke. Once I changed the fuel (after I got advice here) all was good. Just thought I'd throw it out there. Let us know what you find.